Function generic_simd_intrinsic

fn generic_simd_intrinsic<'ll, 'tcx>(
    bx: &mut Builder<'_, 'll, 'tcx>,
    name: Symbol,
    callee_ty: Ty<'tcx>,
    fn_args: GenericArgsRef<'tcx>,
    args: &[OperandRef<'tcx, &'ll Value>],
    ret_ty: Ty<'tcx>,
    llret_ty: &'ll Type,
    span: Span,
) -> Result<&'ll Value, ()>